Fabrication of maxillofacial surgical splints

ABSTRACT

A technique for fabricating a surgical splint for use in correcting a dental condition of a patient. The technique involves obtaining a three-dimensional digital model of lower and upper arch dentitions of the patient having the dental condition. Relative positions of the lower and upper arch dentitions are adjusted with respect to each other in the three-dimensional digital model using a computing device. A relative positioning structure is added to the three-dimensional digital model using the computing device. A physical model of the patient&#39;s corrected dentition is then generated from the three-dimensional digital model. The physical model includes the relative positioning structure that connects the lower and upper arch dentitions of the physical model at the adjusted relative position. The surgical splint is then formed using the physical model. A non-surgical splint is also described.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Application Ser.No. 61/678,934 filed on Aug. 2, 2012, entitled FABRICATION OFMAXILLOFACIAL SURGICAL SPLINTS, the disclosure of which is incorporatedby reference herein in its entirety.

BACKGROUND

Maxillofacial surgery can be used to correct various deformities in thejaws. For example, maxillofacial surgery can be performed to addressClass II overjet or Class III negative overjet. A Class II overjetoccurs when the maxilla and upper teeth project further than themandible and lower teeth. A Class III negative overjet is observablewhen the mandible and lower teeth project further than the maxilla andupper teeth.

Some maxillofacial surgery requires detaching the mandible. Then, therelative positioning of the maxilla and mandible is repositioned so thatthe Class II or Class III issue has been corrected. Splints aresometimes employed to maintain the maxilla and mandible at desiredpositions during the surgical procedure.

Splints are also sometimes used to change the positions of the upper andlower dentions for non-surgical purposes, including treatment oftemporomandibular joint (TMJ) disorder or sleep apnea.

SUMMARY

In general terms, this disclosure is directed to the fabrication ofmaxillofacial surgical splints. In one possible configuration and bynon-limiting example, the surgical splints are formed by using a modelof the patient's dentition, where the model exhibits the desiredrelative positioning of the patient's dentition. In some embodiments thedesired relative positioning is defined using an electronic modelmanipulation engine.

One aspect is a method of fabricating surgical splints for use in asurgical procedure. The method includes: obtaining a three-dimensionaldigital model of lower and upper arch dentitions of a patient having adental condition; adjusting the relative position of the lower and upperarch dentitions with respect to each other in the three-dimensionaldigital model using a computing device; adding at least one relativepositioning structure to the three-dimensional digital model using thecomputing device; generating a physical model of the patient's correcteddentition from the three-dimensional digital model, the physical modelincluding the at least one relative positioning structure that connectsthe lower and upper arch dentitions of the physical model at theadjusted relative position; and forming a surgical splint using thephysical model.

Another aspect is a physical model of a dentition of a patient, whereinthe patient has a dental condition in which the upper and lowerdentitions are in undesired relative positions. The physical modelincludes a physical model of the upper dentition; a physical model ofthe lower dentition; and a non-adjustable relative positioning structurearranged and configured to connect the physical models of the upper andlower dentitions in proper relative positions different from theundesired relative positions of the patient's upper and lowerdentitions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a schematic block diagram illustrating an examplesystem for making and using a maxillofacial surgical splint.

FIG. 2 illustrates a side view of an example three-dimensionalelectronic model of dentition.

FIG. 3 illustrates a side view of an example three-dimensionalelectronic model of a patient's dentition.

FIG. 4 illustrates an example architecture of a computing device, whichcan be used to implement aspects according to the present disclosure.

FIG. 5 illustrates a schematic block diagram illustrating an exampleelectronic model manipulation engine.

FIG. 6 illustrates a flow chart showing an example method of correctingimproper alignment of the maxilla and the mandible.

FIG. 7 illustrates a side view of an example three-dimensionalelectronic model with corrected positioning of the maxilla and mandible.

FIG. 8 illustrates a screenshot of the upper arch dentition withrelative positioning structures.

FIG. 9 illustrates a screenshot of the lower arch dentition withrelative positioning structures.

FIG. 10 illustrates a perspective view of an example corrected archdentition model with relative positioning structures.

FIG. 11 illustrates another perspective view of the example correctedarch dentition model with relative positioning structures.

FIG. 12 illustrates a cross sectional view of an example connectionbetween two relative positioning structures.

FIG. 13 illustrates a front view of an example corrected arch dentitionmodel with relative positioning structures.

FIG. 14 illustrates a left-side view of an example corrected archdentition model with relative positioning structures.

FIG. 15 illustrates a right-side view of an example corrected archdentition model with relative positioning structures.

FIG. 16 illustrates a front perspective view of an example physicalmodel of a patient's corrected dentition.

FIG. 17 illustrates a rear perspective view of the example physicalmodel of a patient's corrected dentition with relative positioningstructures.

FIG. 18 illustrates a front perspective view of the example physicalmodel of a patient's corrected dentition with a surgical splint.

FIG. 19 illustrates a rear perspective view of the example physicalmodel of a patient's corrected dentition with relative positioningstructures and with a surgical splint, as shown in FIG. 18.

FIG. 20 illustrates a front perspective view of the surgical splint, asshown in FIG. 18.

DETAILED DESCRIPTION

Various embodiments will be described in detail with reference to thedrawings, wherein like reference numerals represent like parts andassemblies throughout the several views. Reference to variousembodiments does not limit the scope of the claims attached hereto.Additionally, any examples set forth in this specification are notintended to be limiting and merely set forth some of the many possibleembodiments for the appended claims.

FIG. 1 is a schematic block diagram illustrating an example of a system100 for making and using a maxillofacial surgical splint 108. In thisexample, the system 100 includes a scanning station 110, an orthognathiclab 112, and an operating room 114. The example scanning station 110includes a dentition scanner 102 that generates an electronic model of apatient's dentition 104. The example orthognathic lab 112 includes acomputing device 120, an electronic model manipulation engine 122, acorrected arch dentition model 124, a three-dimensional printer 126, aphysical model of corrected dentition 128, and a splint forming station130. The resulting physical splint can be used for orthognathic surgeryin an operating room 114, for example, which can include an operatingtable 140. Also illustrated in FIG. 1 are examples of several peoplethat may be involved with the system 100, including the patient P,orthodontist O, and surgeon S.

The scanning station 110 operates to perform a scan of the patient's Pdentition, such as using a dentition scanner 102. In some embodiments,the patient P has been identified as having a dental condition in whichthe relative positioning of the maxillary and mandibular dentitionsneeds to be surgically adjusted. Several examples of such dentalconditions include, but are not limited to, a Class II overjet or ClassIII negative overjet, temporomandibular joint (TMJ) disorder, or sleepapnea.

The scanner 102 operates to perform a scan of the patient's dentition.The scanner 102 can be one of several types, for example, including anintraoral scanner, a table top laser scanner, or a computed tomography(CT) scanner. In some embodiments, the scanner is a three-dimensionallaser scanner that generates data defining a polygonal mesh forming theelectronic model 104 of the dentition. In some embodiments, the scanner102 first projects points onto the surface, here, the patient'sdentition. The reflection of these points off of the patient's dentitionenables the scanner to obtain the location of points in athree-dimensional coordinate system (x, y, z). These points are used tocreate a point cloud corresponding to the contours of the patient'sdentition. Next, the scanning system creates a polygonal mesh by usingthe point cloud to create triangles that approximate the surfacecontours. Examples of scanners 102 include a 3D scanner, intraoralscanner, 3D intraoral scanner, or 3D dental scanner. The electronicmodel may be obtained by placing the scanner in the patient's mouth, byscanning a dental impression, or by scanning from outside of the mouth.Several examples of possible scanners 102 include: the TRIOS Intra OralDigital Scanner, the Lava Chairside Oral Scanner C.O.S., the iTero, theCerec AC, the Cyrtina IntraOral Scanner, a cone beam CT (CBCT) scanner,and an industrial CT scanner.

The electronic model of the dentition 104 includes, for example, themaxillary and mandibular dentition, and shows the undesired relativepositioning of each that needs to be surgically corrected. Examples ofsuch electronic models 104 are illustrated and described in more detailherein with reference to FIGS. 2 and 3.

The orthognathic lab 112 generates a physical splint 108 for use duringthe surgical procedure, using the electronic model of dentition 104. Theexample orthognathic lab 112 includes a computing device 120 includingan electronic model manipulation engine 122, a three-dimensional printer126, and a splint forming station.

The computing device 120 operates to generate a corrected arch dentition124 using the electronic model of dentition 104. An example of thecomputing device 120 is illustrated and described in more detail hereinwith reference to FIG. 4. In some embodiments, the computing device 120includes an electronic model manipulation engine 122. The user, such asan orthodontist, interacts with the computer 120 and electronic modelmanipulation engine to adjust the relative positioning of the maxillaryand mandibular dentitions, and to insert a relative positioningstructure, as discussed in more detail herein, to form a corrected archdentition model 124. An arch dentition includes the dentition, gingiva,and contour of a patient's upper or lower jaw. An example of theelectronic model manipulation engine 122 is illustrated and described inmore detail herein with reference to FIGS. 5-6.

The three-dimensional printer 126 operates to generate a physical model128 from the corrected arch dentition model 124. In some embodiments,the three-dimensional printer 126 uses an additive process of depositingsuccessive layers of material onto a surface to manufacture a desiredobject. Electronic three-dimensional models provide the blueprint forthe three-dimensional printer: software takes the object within theelectronic model and creates thin, horizontal cross-sections which canbe used to direct the printer to deposit material at locations definedby the electronic model. Examples of additive technologies includeselective laser sintering, fused deposition modeling, stereolithography, powder bed and inkjet head 3D printing, and plaster-based3D printing. An example of a three-dimensional printer 126 is theProJect line of 3D printers available from 3DSystems, Inc. of Rock Hill,S.C. Other examples of three-dimensional printers 126 are thoseavailable from Stratysis, Inc. of Eden Prairie, Minn., and Objet Ltd ofRehovot, Israel. In some embodiments the three-dimensional printer 126is an inkjet printer that utilizes prints using a polymeric material. Inanother embodiment, the printer 126 is a stereolithography printer thatutilizes a photocurable polymer. Other embodiments use otherthree-dimensional printers. An example of a physical model 128 createdby the three-dimensional printer 126 from the corrected arch dentitionmodel 124 are shown in FIGS. 16 and 17.

The splint forming station 130 uses the physical model 128 to form aphysical splint 108 that can be used during a surgical procedure. Insome embodiments, production of the surgical splint 108 involvesinserting a pliable material, such as a light-curable resin, into aspace between the upper and lower arch dentitions. In some embodiments,a non-stick coating is first applied to the upper and lower archdentitions to permit the surgical splint to be more easily separatedfrom the physical model. The pliable material contacts at least some ofthe teeth of the physical model and is therefore formed with imprintsfrom the teeth that substantially match the shape of the patient'sactual teeth. In some embodiments, the material is then cured byilluminating with an ultraviolet light, which hardens the material anddecreases its pliability. One example of a suitable material that can beused to form the splint 108 is the TRIAD® transparent VLC custom traymaterial available from Dentsply International Inc., of York, Pa. Insome embodiments, the material is a filled photocure dimethacrylate thatpolymerizes through exposure to 400- to 500-nm wavelengths ultraviolet-Alight.

In some embodiments, the splint material has a paste consistency whichcan be applied by hand onto the physical model 128. A non-stick materialcan be applied to the physical model 128 prior to application of thesplint material to assist in removal of the splint after it has beenformed. The splint material is then placed onto the teeth of one of theupper or lower dentitions 162 and 164, and then the other dentition 162or 164 is properly positioned using the relative positioning structures,causing the dentitions 162 and 164 to form imprints in the splintmaterial. The splint material can then be hardened by exposing to UVlight. The completed splint 108 is then removed from the physical model128 and is ready for use. In some embodiments, the splint 108 issterilized prior to use in a surgical environment of the operating room114.

The surgical splint 108 is formed by the splint forming station, and canbe used in some embodiments during a surgical procedure in the operatingroom 114 to assist in proper positioning of the patient's P maxillaryand mandibular dentitions. An example of the surgical splint 108 isillustrated and described in more detail with reference to FIGS. 17-20.In other embodiments, the splint is a non-surgical splint that can beused, for example, to treat TMJ or sleep apnea.

In some embodiments, the surgical procedure is performed by a surgeon Sin an operating room 114. The patient P can be supported on an operatingtable 140 or chair during the procedure. During an exemplary procedure,the patient's mandible is broken or cut to permit movement of themandible. The surgical splint 108 is placed into the patient's mouth,and the maxillary and mandibular dentitions are properly aligned andpositioned by locating the teeth in indentations in the surgical splint108. The mandible is then reconnected to maintain the proper position ofthe mandible.

FIG. 2 illustrates an example of a side view of a three-dimensionalelectronic model of dentition 104, generated by the scanner 102, shownin FIG. 1. The illustrated electronic model 104A shows an example inwhich the patient has a Class II overjet, which can be identified by therelative positioning of the upper arch dentition 162 and the lower archdentition 164. A Class II overjet can also be identified, for example,by the distance D1 between corresponding points on the upper dentition162 and the lower dentition 164, where the upper dentition 162 extendsforward farther than the lower dentition 164.

In some embodiments, overjet is identified by reference to particularpoints on the upper and lower dentitions 162 and 164. An example of suchpoints include the points P1 and P2. Point P1 is the location of themost anterior cusp of the first molar on the upper dentition 162. PointP2 is the location between the anterior and posterior cusps of the lowerfirst molar. In this example, it can be seen that there is a relativelylarge spacing between points P1 and P2, represented by distance D1, andthe point P1 is forward of the point P2. Similarly, corresponding pointson the other sides of the dentitions P1 and P2 can be evaluated.Finally, the alignment of the central incisors can be compared from theupper and lower dentitions 162 and 164, as it is typically preferredthat the central incisors be aligned on the upper and lower dentitions162 and 164.

The electronic model 104A of the upper arch dentition 162 defines thecontours of the maxillary gingiva 166 and the maxillary teeth 168.Similarly, the electronic model 104A of the lower arch dentition 164defines the contours of the mandibular gingiva 170 and the mandibularteeth 172. An example of a corrected relative positioning of the upper162 and lower 164 dentitions is shown in more detail in FIG. 7.

FIG. 3 illustrates an example of a side view of a three-dimensionalelectronic model of a patient's dentition 104, generated by the scanner102, shown in FIG. 1. The illustrated electronic model 104B shows anexample of a Class III negative overjet, which can be identified by therelative positioning of the upper arch dentition 162 and the lower archdentition 164. A Class II overjet can also be identified, for example,by the distance D2 between two or more corresponding points on the upperdentition 162 and the lower dentition 164, where the lower dentition 164extends forward farther than the upper dentition 162.

In some embodiments, negative overjet is identified by reference toparticular points on the upper and lower dentitions 162 and 164. Anexample of such points include the points P1 and P2, as discussed above.Point P1 is the location of the most anterior cusp of the first molar onthe upper dentition 162. Point P2 is the location between the anteriorand posterior cusps of the lower first molar. In this example, it can beseen that there is a relatively large spacing between points P1 and P2,represented by distance D2, and the point P2 is forward of the point P1.

The electronic model 104B of the upper arch dentition 162 defines thecontours of the maxillary gingiva 166 and the maxillary teeth 168.Similarly, the electronic model 104A of the lower arch dentition 164defines the contours of the mandibular gingiva 170 and the mandibularteeth 172. An example of a corrected relative positioning of the upper162 and lower 164 dentitions is shown in more detail in FIG. 7.

FIG. 4 illustrates an exemplary architecture of a computing device thatcan be used to implement aspects of the present disclosure, includingany of the plurality of computing devices described herein, such as acomputing device of the dentition scanner 102, the electronic modelmanipulation engine 122, a computing device of the three dimensionalprinter 126, or any other computing devices that may be utilized in thevarious possible embodiments. The computing device illustrated in FIG. 4can be used to execute the operating system, application programs, andsoftware modules (including the software engines) described herein. Byway of example, the computing device will be described below as thecomputing device 120 that operates the electronic model manipulationengine 122. To avoid undue repetition, this description of the computingdevice will not be separately repeated herein for each of the otherpossible computing devices, but such devices can also be configured asillustrated and described with reference to FIG. 4.

The computing device 120 includes, in some embodiments, at least oneprocessing device 180, such as a central processing unit (CPU). Avariety of processing devices are available from a variety ofmanufacturers, for example, Intel or Advanced Micro Devices. In thisexample, the computing device 120 also includes a system memory 182, anda system bus 184 that couples various system components including thesystem memory 182 to the processing device 180. The system bus 184 isone of any number of types of bus structures including a memory bus, ormemory controller; a peripheral bus; and a local bus using any of avariety of bus architectures.

Examples of computing devices suitable for the computing device 120include a desktop computer, a laptop computer, a tablet computer, amobile computing device (such as a smart phone, an iPod® or iPad® mobiledigital device, or other mobile devices), or other devices configured toprocess digital instructions.

The system memory 182 includes read only memory 186 and random accessmemory 188. A basic input/output system 190 containing the basicroutines that act to transfer information within computing device 120,such as during start up, is typically stored in the read only memory186.

The computing device 120 also includes a secondary storage device 192 insome embodiments, such as a hard disk drive, for storing digital data.The secondary storage device 192 is connected to the system bus 184 by asecondary storage interface 194. The secondary storage devices 192 andtheir associated computer readable media provide nonvolatile storage ofcomputer readable instructions (including application programs andprogram modules), data structures, and other data for the computingdevice 120.

Although the exemplary environment described herein employs a hard diskdrive as a secondary storage device, other types of computer readablestorage media are used in other embodiments. Examples of these othertypes of computer readable storage media include magnetic cassettes,flash memory cards, digital video disks, Bernoulli cartridges, compactdisc read only memories, digital versatile disk read only memories,random access memories, or read only memories. Some embodiments includenon-transitory media. Additionally, such computer readable storage mediacan include local storage or cloud-based storage.

A number of program modules can be stored in secondary storage device192 or memory 182, including an operating system 196, one or moreapplication programs 198, other program modules 200 (such as thesoftware engines described herein), and program data 202. The computingdevice 120 can utilize any suitable operating system, such as MicrosoftWindows™, Google Chrome™, Apple OS, and any other operating systemsuitable for a computing device. Other examples can include Microsoft,Google, or Apple operating systems, or any other suitable operatingsystem used in tablet computing devices.

In some embodiments, a user provides inputs to the computing device 120through one or more input devices 204. Examples of input devices 204include a keyboard 206, mouse 208, microphone 210, and touch sensor 212(such as a touchpad or touch sensitive display). Other embodimentsinclude other input devices 204. The input devices are often connectedto the processing device 180 through an input/output interface 214 thatis coupled to the system bus 184. These input devices 204 can beconnected by any number of input/output interfaces, such as a parallelport, serial port, game port, or a universal serial bus. Wirelesscommunication between input devices and the interface 214 is possible aswell, and includes infrared, BLUETOOTH® wireless technology,802.11a/b/g/n, cellular, or other radio frequency communication systemsin some possible embodiments.

In this example embodiment, a display device 216, such as a monitor,liquid crystal display device, projector, or touch sensitive displaydevice, is also connected to the system bus 184 via an interface, suchas a video adapter 218. In addition to the display device 216, thecomputing device 120 can include various other peripheral devices (notshown), such as speakers or a printer.

When used in a local area networking environment or a wide areanetworking environment (such as the Internet), the computing device 120is typically connected to the network through a network interface 220,such as an Ethernet interface. Other possible embodiments use othercommunication devices. For example, some embodiments of the computingdevice 120 include a modem for communicating across the network.

The computing device 120 typically includes at least some form ofcomputer readable media. Computer readable media includes any availablemedia that can be accessed by the computing device 120. By way ofexample, computer readable media include computer readable storage mediaand computer readable communication media.

Computer readable storage media includes volatile and nonvolatile,removable and non-removable media implemented in any device configuredto store information such as computer readable instructions, datastructures, program modules or other data. Computer readable storagemedia includes, but is not limited to, random access memory, read onlymemory, electrically erasable programmable read only memory, flashmemory or other memory technology, compact disc read only memory,digital versatile disks or other optical storage, magnetic cassettes,magnetic tape, magnetic disk storage or other magnetic storage devices,or any other medium that can be used to store the desired informationand that can be accessed by the computing device 120.

Computer readable communication media typically embodies computerreadable instructions, data structures, program modules or other data ina modulated data signal such as a carrier wave or other transportmechanism and includes any information delivery media. The term“modulated data signal” refers to a signal that has one or more of itscharacteristics set or changed in such a manner as to encode informationin the signal. By way of example, computer readable communication mediaincludes wired media such as a wired network or direct-wired connection,and wireless media such as acoustic, radio frequency, infrared, andother wireless media. Combinations of any of the above are also includedwithin the scope of computer readable media.

The computing device illustrated in FIG. 4 is also an example ofprogrammable electronics, which may include one or more such computingdevices, and when multiple computing devices are included, suchcomputing devices can be coupled together with a suitable datacommunication network so as to collectively perform the variousfunctions, methods, or operations disclosed herein.

FIG. 5 is a schematic block diagram illustrating an example of anelectronic model manipulation engine 122. In this example, the modelmanipulation engine 122 includes a three-dimensional electronic modelviewer 260, measurement and manipulation tools 262, and a relativepositioning structure generator 264. Also illustrated in FIG. 5 are theelectronic model of dentition 104 and the corrected arch dentition model124 with relative positioning structure.

The three-dimensional electronic model viewer 260 operates to displaythe electronic model of dentition 104 generated by the dentition scanner102 to a user, such as the orthodontist O, so that the user can view it.In one embodiment, the electronic model viewer 260 reads the receivedelectronic model 104 data and renders the electronic model 104 viewablein the computing device 120. In some embodiments, the electronic modelviewer 260 converts the file type of the received electronic model 104into another format readable by the computing device 120, prior todisplaying the electronic model of dentition 104 to the user O. Anexample of a three-dimensional electronic model viewer is the EMODEL®Viewer, such as version 8.5, available from GeoDigm Corporation, ofFalcon Heights, Minn.

The measurement and manipulation tools 262 enable the user O toreposition the relative alignment of the upper 162 and lower 164 archmodels. In one embodiment, the tools 262 render the upper 162 and lower164 arch models independently maneuverable. In some embodiments, theuser O utilizes the tools 262 to adjust the relative positions of thearch dentitions. The user O can reposition both the upper 162 and lower164 arch models in any of the x-, y-, or z-planes to correct thediagnosed condition. In another embodiment, the tools 262 measure therelative positions of two or more corresponding points on the upper 162and lower 164 arch models to obtain a distance D3. In this embodiment,the tools 262 are programmed to automatically compare the new distanceD3 with a pre-defined metric automatically positioning the upper 162 andlower 164 arch models according to the pre-defined metric.Alternatively, the tools 262 can be used to instruct the user tocontinue repositioning the upper 162 and/or lower 164 arch models if thecurrent relative positioning does not satisfy the metrics. In someembodiments, the measurement and manipulation tools 262 are part of theModified Bite Module of the EMODEL® Viewer software application. Forexample, manipulation of the electronic model can be accomplished usingthe rotate x-y-z and translate x-y-z functions. Measurement can beaccomplished, for example, using the measurement grid function. Inanother possible embodiment, the measurement and manipulation tools 262can be configured to automatically configure the upper and lowerdentitions 262 and 264 according to predefined criteria, or byuser-provided criteria, such as desired measurements between particularpoints (e.g., P1 and P2 discussed herein, and the alignment of thecentral incisors).

In some embodiments, the tools 262 include a measurement tool formeasuring the distance between at least two points of the upper andlower arch dentitions 162 and 164. An example showing the measurement ofdistance D4 after the repositioning of the upper 162 and lower 164 archdentitions, is illustrated and described in more detail with referenceto FIG. 7.

The relative positioning structure generator 264 operates to add to theelectronic model 104 structures that will hold and maintain the relativepositioning of the upper and lower arch dentitions 162 and 164, afterthe position of such arch dentitions 162 and 164 has been corrected inthe electronic model 104. The relative positioning structure generatoris illustrated and described in more detail with reference to FIG. 6.

FIG. 6 is a flow chart illustrating an example method 266 of correctingan improper alignment of the maxilla and the mandible. In this example,the method 266 includes operation 268 and methods 270 and 280. Themethod 266 transforms an electronic model of improperly aligned maxillaand mandible into a corrected model where the maxilla and mandible areproperly aligned and the model has one or more relative positioningstructures.

Operation 268 is performed to enable the user to view the electronicmodel of dentition 104. In some embodiments, operation 268 is performedby the three-dimensional electronic model viewer 260, shown in FIG. 5.

In this example, the method 270 is performed to adjust the relativepositioning of the upper 162 and lower 164 dentition models, where thecorrected relative positions are illustrated and described in moredetail with reference to FIG. 7. The method includes operations 272,274, and 276. In some embodiments, the method 270 is performed by thethree-dimensional electronic model viewer 260 and the measurement andmanipulation tools 262, shown in FIG. 5.

Operation 272 is performed to adjust the relative positions of the upper162 and lower 164 arch dentitions. In some embodiments, the operation272 interacts with the user to manipulate the relative positions of thearch dentitions 162 and 164. Based on the patient's condition, theoperation 272 prompts the user O to reposition the patient's maxilla andmandible in the x-y plane, and receives inputs from the user to make theappropriate adjustments.

Operation 274 is performed to measure the relative positions of theupper 162 and lower 164 arch dentitions. In some embodiments, theoperation 274 identifies two corresponding points on the upper 162 andlower 164 arch dentitions. As an example, the operation 274 calculatesthe distance, see D3 in FIG. 7, in the x-y-plane between two lines thatpass through the identified points, where the lines are normal to thex-y-plane. For example, the operation 274 may select points on thelabial surface of the maxillary and mandibular central incisors. Inother embodiments, the operation 274 calculates the vertical distancebetween two corresponding points, see D4 in FIG. 7, on the upper 168 andlower 172 dentitions. For example, the operation 274 may select pointson the occlusal surface of the 2^(nd) molars and calculate the verticalor z-plane distance between those points.

Operation 276 is performed to verify that the relative positioning ofthe upper 162 and lower 164 arch dentitions conforms to desired metrics.In some embodiments, pre-defined parameters are stored. An example ofpre-defined parameters are metrics related to the required relativehorizontal (x-y plane) positions of the upper 162 and lower 164 archdentitions needed to correct the observed deficiency. Another example ofpre-defined parameters are metrics corresponding to the manufacturingcharacteristics of the splint forming station 130. These parametersmeasure the z-plane or vertical distance between the upper 168 and lower172 dentition.

In some embodiments, the operation 276 compares the relative position ofthe upper 162 and lower 164 arch dentitions. As an example, if thepositions do not correspond to the desired metrics, the operation 276prompts the user to readjust the relative positions in operation 272 andthe process repeats until the arch dentitions are acceptably positioned.In one embodiment, if the relative positions do not conform to thepre-stored metrics, the operation 276 reposition the upper 162 and lower164 arch dentitions so that the relative positions satisfy the metriccriteria. As another example, if the positions are within acceptabletolerances of the pre-stored metrics, the operation 276 prompts the userto complete the model with operations 280 and 282. An example of acorrected arch dentition model 278 is illustrated and described in moredetail with reference to FIG. 7.

In this example, the method 280 is performed to add relative positioningstructures to the model. The method includes operations 282 and 284. Insome embodiments, the method 280 is performed by the three-dimensionalelectronic model viewer 260 and the relative positioning structuregenerator 264, shown in FIG. 5. In some embodiments, the method 280begins when the engine accesses the corrected arch dentition model 278.In some embodiments, the method 280 may be performed by a user who isnot the orthodontist O.

Operation 282 is performed to add one or more relative positioningstructures to the arch dentition model 278. In some embodiments, theoperation 282 prompts the user to select a type of relative positioningstructure from a database containing templates for different relativepositioning structures.

In one embodiment, the operation 282 prompts the user to select aposition for the relative positioning structure on the lower archdentition 164, and the operation 282 receives the input from the user.In some embodiments, the operation 282 continues to prompt the user toselect positions of additional relative positioning structures.Alternatively, the operation 282 prompts the user to select a positionfor the upper arch dentition 162 first; the order is not important. Insome embodiments, the operation 282 adds one or more complementaryrelative positioning structures to the opposite dentition. In oneembodiment, the operation 282 creates the relative positioningstructures by accessing the templates defining the properties of therelative positioning structures.

FIGS. 8-15 illustrate an example of relative positioning structures ashaving cylindrical bases with male and female couplings, where the malecoupling is in the shape of a truncated cone. This is only an example.In other possible embodiments, other shapes, configurations, andquantities of relative positioning structures can be used. Some examplesinclude where the relative positioning structure is between or locatedon outside the upper and lower arch dentition. For example, a singlestructure that simultaneously holds the upper 162 and lower 164 archdentitions, which is between the arch dentitions, or a c-shapedstructure that holds the two arch dentitions without passing between thearch dentitions. In other embodiments, the relative positioningstructure is a single structure, in contrast to the three structuresshown in more detail in FIGS. 8-11, where the body has a larger surfacearea than the structures shown in FIGS. 8-11. In yet other embodiments,the relative positioning structure is two or more structures. In someembodiments, the relative positioning structures have bodies in otherpolyhedron shapes, such as triangular or rectangular prisms, in contrastto the cylindrical bodies shown in more detail in FIGS. 8-11. An exampleof the relative positioning structure is illustrated and described withreference to FIGS. 8-11.

Operation 284 is performed in some embodiments to ensure that therelative positioning structure or structures do not interfere with thesubsequent surgical splint formation. In some embodiments, the operation284 prompts the user to check the location of the relative positioningstructure created by the operation 284 on the opposite dentition. Inother embodiments, the operation 284 notifies the user that the currentposition of the relative positioning structure could interfere with theproduction of the surgical splint. As an example, the operation 284accesses a database containing the various space requirements fordifferent surgical splint production methods. Examples of suchrequirements could be the predicted width, in the x-y-plane, of surgicalsplints formed using different materials.

In some embodiments, the operation 284 receives the user's selection ofnew positions for the relative positioning structures. As an example,after receiving the user's input, the operation 284 updates the positionof the complementary positioning structure. In one embodiment, theoperation 284 repeats until the relative positioning structure orstructures do not potentially interfere with the surgical splintproduction. In other embodiments, once the operation 284 has receivedthe user's input selecting relative positioning structures, the model124 is ready for the three-dimensional printer 126.

FIG. 7 illustrates a side view of an example of a corrected archdentition model 278, such as generated by the method 270 shown in FIG.6. In this example, the model 278 includes the upper 162 and lower 164arch dentitions, the maxillary 166 and mandibular 170 gingiva, and theupper 168 and lower 172 dentition. In this example, upper 162 and lower164 arch dentitions are positioned to correct the diagnosed condition ofthe patient P.

In some embodiments, the horizontal distance D3 is the distance in thex-y-plane between corresponding points on the upper 162 and lower 164arch dentitions. In some embodiments, the two corresponding points arethe same points used in measuring and obtaining the horizontal distanceD1 or D2, as shown in FIGS. 2 and 3. In some embodiments, the verticaldistance D4 is the distance in the x-z- or y-z-plane between twocorresponding points on the upper 162 and lower 164 arch dentitions. Insome embodiments, the electronic model manipulation engine 122 is usedto obtain the model shown in FIG. 7.

FIG. 8 is a screenshot of the upper arch dentition 162 with relativepositioning structures 290 as displayed by the electronic modelmanipulation engine 122, shown in FIG. 5. The screenshot shows the upperarch dentition 162, the upper dentition 168, the maxillary gingiva 166,and the location 292 of the relative positioning structures 290.

The relative positioning structure 290 functions to hold the upper 162and lower 164 arch dentitions in the adjusted relative positions. Insome embodiments, the relative positioning structures 290 in the upperarch dentition 162 have a shape that is complementary to the relativepositioning structures 294, shown in FIG. 9, in the lower arch dentition164. The relative positioning structures 290 are shown and described inmore detail in FIGS. 10 and 12.

The location 292 of the relative positioning structures 290 functions toenable the relative positioning structures 290 to hold the physicalmodel 128 in the adjusted positions without interfering with thesurgical splint 108 production. In one embodiment, the engine 122prompts the user to select a position 292 of a relative positioningstructure 290, as described in operation 282. As an example, the engine122 receives the input selecting the position 292, where the position292 is preferably not in contact with the maxillary gingiva 166 or upperdentition 168. In another embodiment, the engine 122 prompts the userfor the position 292 of two more relative positioning structures 290.

In some embodiments, the engine 122 corrects the location 292 of therelative positioning structures 290 so the structures do not interferewith the surgical splint 108 production. As an example, the engine 122has verified that the location 292 of the relative positioningstructures 290 in FIG. 8 do not interfere with the splint 108production. The location 292 of the relative positioning structures 290is also illustrated in FIG. 10.

FIG. 9 is a screenshot of the lower arch dentition 164 with relativepositioning structures 294. The screenshot shows the lower archdentition 164, the lower dentition 172, the mandibular gingiva 170, andthe location 296 of the relative positioning structures 294.

The relative positioning structure 294 functions to hold the upper 162and lower 164 arch dentitions in the adjusted relative positions 278. Insome embodiments, the relative positioning structures 294 in the lowerarch dentition 164 have a shape that is complementary to the relativepositioning structures 290, shown in FIG. 8, in the upper arch dentition162. The relative positioning structures 294 are shown and described inmore detail in FIGS. 11 and 12.

The location 296 of the relative positioning structures 294 functions toenable the positioning structures 294 to hold the physical model 128 inthe adjusted positions without interfering with the surgical splint 108production. In one embodiment, the engine 122 prompts the user to selecta position 296 of a relative positioning structure 294, as described inoperation 282. As an example, the engine 122 receives the inputselecting the position 296, where the position 296 is preferably not incontact with the mandibular gingiva 170 or lower dentition 172. Inanother embodiment, the engine 122 prompts the user for the position 296of two more relative positioning structures 294.

In some embodiments, the engine 122 corrects the location 296 of therelative positioning structures 294 so the structures do not interferewith the surgical splint 108 production. As an example, the engine 122has verified that the location 296 of the relative positioningstructures 294 in FIG. 9 do not interfere with the splint 108production. The location 296 of the relative positioning structures 294is also described in FIG. 11.

FIG. 10 illustrates a perspective view of an example corrected archdentition model 124 with relative positioning structures 290. Theillustrated model shows an example of an upper arch dentition 162 inwhich there are three relative positioning structures 290 with a givenradius R. Also illustrated is the location 292 of the structures 290,including an example coupling feature 300 and a body 302. The upperdentition 168 and the maxillary gingiva 166 are also shown.

The location 292 of the relative positioning structures 290 in FIG. 10functions to stably connect to the lower arch dentition 164 while alsonot interfering with surgical splint 108 production.

The female coupling 300 on the relative positioning structure 290receives the male coupling 308 from the opposite arch dentition. In oneembodiment, the relative positioning structures 290 and 294 havecomplementary female 300 and male 308 couplings. In one embodiment, thefemale coupling 300 has a recessed portion that is sized and shaped toreceive the corresponding protruding portion of the male coupling 308(shown in FIG. 11). In this example, the female coupling 300 is on therelative positioning structures 290 in the upper arch dentition 162, butthe engine can place the female coupling 300 on either the upper 162 orthe lower 164 arch dentition. An example of a male-female couplinginteraction is shown in more detail in FIG. 12.

The body 302 extends between the arch dentition 162 and the coupling300. In some embodiments, the body 302 protrudes normal to the x-y-planefrom the upper arch dentition 162. In one embodiment, the contours ofthe upper arch 162 flow seamlessly with the body 302 so that thethree-dimensional printer 126 produces the upper arch 164 andpositioning structures 290 as one continuous piece. In some embodiments,the body 302 of the relative positioning structure 290 is cylindricallyshaped. In some embodiments, the engine 122 accesses a template which isused to create the relative positioning structure. As an example, theengine 122 receives the user's point selection of the center 292 of thepositioning structure 290 as well as the desired radius R of thecylindrical body 302 extending therefrom. As another example, the engine122 receives the user's selection of the height of the cylindrical body302. The bodies and the connected relative positioning structures areshown in more detail in FIGS. 13-15.

FIG. 11 illustrates a perspective view of an example corrected archdentition model 124 with relative positioning structures 294. Theillustrated model shows an example of a lower arch dentition 164 inwhich there are three relative positioning structures 290 with a givenradius R. Also illustrated is the location 296 of the relativepositioning structures 294, an example male coupling 308 and supportbody 306 of a positioning structure, the lower dentition 172, and themandibular gingiva 170.

The location 296 of the relative positioning structures 294 in FIG. 11functions to stably connect to the upper arch dentition 162 while alsonot interfering with surgical splint 108 production.

The male coupling 308 on the relative positioning structure 294 fitsinto the female coupling 300 of the relative positioning structure 290of the opposite arch dentition. In one embodiment, the relativepositioning structures 290 and 294 have complementary female 300 andmale 308 couplings. In one embodiment, the male coupling 308 is atruncated cone. In this example, the male coupling 308 is on therelative positioning structures 294 in the lower arch dentition 164, butthe engine can place the male coupling 308 on either the upper 162 orthe lower 164 arch dentition. An example of a male-female couplinginteraction is shown in more detail in FIG. 12.

The body 306 supports the coupling 308. In some embodiments, the body306 protrudes normal to the x-y-plane from the lower arch dentition 164.In one embodiment, the contours of the upper arch 162 flow seamlesslywith the body 302 so that the three-dimensional printer 126 produces theupper arch 164 and relative positioning structures 290 as one continuouspiece. In some embodiments, the body 306 of the relative positioningstructure 294 is cylindrically shaped. In some embodiments, the engine122 accesses a template which is used to create the relative positioningstructure. As an example, the engine 122 receives the user's pointselection of the center of the positioning structure 296 as well as thedesired radius R of the cylindrical body 306 extending therefrom Asanother example, the engine 122 receives the user's selection of theheight of the cylindrical body 306. The bodies and the connectedrelative positioning structures are shown in more detail in FIGS. 13-15.

FIG. 12 is a cross sectional view of the connection 301 between twoexample relative positioning structures 290 and 294. In this example,the connection 301 is between a female 300 and male 308 coupling,supported by the bodies 302 and 306 respectively, forming a snug fit 314and 316, with voids 310 and 312. In other embodiments, the engineaccesses templates containing different designs of relative positioningstructures when the engine adds the positioning structures to theelectronic model in operation 282. The connection 301 is shown in moredetail in FIGS. 13-15.

The void 310 enables the male coupling 308 to fit within the femalecoupling 300 even if debris has settled within the female end's cavityor on the end of the male coupling. In some embodiments, the void's 310space is formed between the top of the truncated cone male coupling 308and the deepest part of the female coupling 300.

The voids 310 and 312 enable a snug fit between the male coupling 308and the female coupling 300 even if debris has settled near the openingof the female coupling 300 or on the male coupling 308 close to wherethe coupling 308 meets the body 306. In some embodiments, the void 312space is formed near the opening of the female coupling 300 and the bodyof the male coupling 308.

The two couplings 300 and 308 form a snug fit within the female coupling314 and where the bodies meet 316. In some embodiments, the lateralsurface of the male coupling 308 is flush with the lateral surface ofthe female coupling 300, forming an interface 314 where the twocouplings are, or nearly are, in direct contact. In some embodiments,the surface of the bodies 302 and 306 that is parallel to the x-y-planeform an interface 316 where the two bodies are, or nearly are, in directcontact. In the preferred embodiment, the snug fit ensures that theupper 162 and lower 164 arch dentitions do not change their relativepositions during the surgical splint forming (at station 130).

FIGS. 13-15 illustrate different views of the corrected arch dentitionmodel 124 with connected relative positioning structures 328. FIG. 13 isa front view illustrating the upper 162 and lower 164 arch dentitions,the maxillary 166 and mandibular 170 gingiva, the upper 168 and lower172 dentition, the connected relative positioning structures 328, andthe midpoint x-y-plane 326 between the upper 162 and lower 164 archdentitions. FIG. 14 is a left-side view illustrating the connectedrelative positioning structures 328. FIG. 15 is a right-side view alsoillustrating the connected relative positioning structures 328.

The connected relative positioning structures 328 hold the upper 162 andlower 164 dentitions in the relative positions defined by theorthodontist O 278. In a preferred embodiment, the upper 290 and lower294 positioning structures interface 301 at the x-y-plane midpoint 326between the upper 162 and lower 164 arch dentitions. In otherembodiments, the interface 301 is located at positions other than thex-y-plane midpoint.

FIG. 16 is a front perspective view of a physical model 128 of apatient's corrected dentition. In this example, the physical model 128includes the upper arch dentition 330 and the lower arch dentition 332.Present, but not visible in FIG. 16, are the connected relativepositioning structures 342 which can be seen in FIG. 17. Additionalexemplary views of the physical model 128 are also shown in FIGS. 17-19.

The upper arch dentition 330 of the physical model 128 of the patient'scorrected dentition is a replication of the patient's upper dentition334 and maxillary gingiva 336. In this embodiment, the physical model's128 upper dentition 334 contours substantially match the patient's Pactual upper dentition contours, so that a surgical splint can be madefrom the physical model 128 that fits snugly into the patient'sdentition. The contours in the splint are shown in more detail in FIG.20. In some embodiments, The upper arch dentition 330 is separable fromthe lower arch dentition 332, but the model 128 can be properly alignedand positioned by the connected relative positioning structures 342. Theupper arch dentition 330 is also depicted in FIGS. 17-19.

The lower arch dentition 332 of the physical model 128 of the patient'scorrected dentition is a replication of the patient's lower dentition340 and mandibular gingiva 338. In this embodiment, the physical model's128 lower dentition 340 contours substantially match the patient's Pactual lower dentition contours, so that a surgical splint can be madefrom the physical model 128 that fits snugly into the patient'sdentition. The contours in the splint are shown in more detail in FIG.20. In some embodiments, the lower arch dentition 332 is separable fromthe upper arch dentition 330, but the model 128 can be properly alignedand positioned by the connected relative positioning structures 342. Thelower arch dentition 332 is also depicted in FIGS. 17-19.

The distance D4 between two corresponding points on the upper 330 andlower 332 arch dentitions provides the space needed for the splint tofit during the operation. In one embodiment, the engine received theuser's input of the distance D4 in methods 270 and 280, shown in moredetail in FIG. 6. In some embodiments, the distance D4 corresponds tothe surgical splint material's properties. In some embodiments, thedistance D4 in the physical model 128 is maintained by the relativepositioning structures 346 depicted in more detail in FIGS. 17 and 19.

FIG. 17 is a rear perspective view of a physical model of a patient'scorrected dentition 128. In this example, FIG. 17 shows the upper 330and lower 332 arch dentitions, and the connected relative positioningstructures 342 formed by the positioning structures attached to theupper 344 and lower 346 arch dentitions. FIG. 19 shows a similar viewwith the surgical splint 108.

The connected relative positioning structures 342 function to hold theupper 330 and lower 332 arch dentitions in the relative positionsdefined by the orthodontist O. In this example, the interface betweenthe upper 344 and lower 346 relative positioning structures occurs atthe midpoint in the z-plane between the upper 330 and lower 332 archdentitions. In some embodiments, the relative positioning structures 344and 346 form a releasable coupling, shown in more detail in FIGS. 10-12.In some embodiments, the connected relative positioning structures 342maintain the distance D4 between corresponding points, as shown in moredetail in FIG. 16, to assist surgical splint formation andfunctionality.

The upper relative positioning structures 344 couple to the lowerpositioning structures 346 to form the connected relative positioningstructures 342. In some embodiments, the upper 344 and lower 346positioning structures extend from the surface contouring the patient'smouth that is not the dentition or gingiva. In some embodiments, theupper 344 and lower 346 positioning structures project a given distanceaway from the dentition so as to not interfere with the splintpositioning or formation. In this example, the positioning structures344 and 346 are cylindrical, as electronically depicted in FIGS. 10-11,and couple as depicted in FIG. 12.

FIG. 18 is a front perspective view of the physical model of thepatient's corrected dentition 128 with the surgical splint 108. In thisexample, FIG. 18 shows the upper 330 and lower 332 arch dentitions, theupper 334 and lower 340 dentitions, and the surgical splint 108. A rearperspective view of the same is shown in FIG. 19, and the surgicalsplint 108 is shown in more detail in FIG. 20.

The surgical splint 108 maintains the relative positioning of the upper330 and lower 332 arch dentitions as defined by the orthodontist O.Surgical splint formation techniques are described in more detail inFIG. 1, with reference to 130 and 108. In some embodiments, the uppersurface of the surgical splint 108 has contours that match the contoursof the patient's upper dentition 334. In some embodiments, the contourshave a depth in a range from about 0.1 mm to about 3 mm. Otherembodiments have other dimensions. Similarly, in some embodiments, thelower surface of the surgical splint 108 has contours that match thecontours of the patient's lower dentition 340. In some embodiments, thecontours have a depth in a range from about 0.1 mm to about 3 mm. Otherembodiments have other dimensions.

FIG. 19 is a rear perspective view of the physical model of thepatient's corrected dentition 128 with the surgical splint 108. In thisexample, FIG. 19 shows the upper 330 and lower 332 arch dentitions, theconnected relative positioning structures 342, and the surgical splint108. The surgical splint 108 is shown in more detail in FIG. 20.

The surgical splint 108 functions to hold the upper 330 and lower 332arch dentitions in the relative positions as defined by the orthodontistO. In this example, the distance D4 between corresponding points is thesame with the surgical splint 108 place between the upper 330 and lower332 arch dentitions. In some embodiments, the connected relativepositioning structures 342 are not in contact with the surgical splint108.

FIG. 20 is a front perspective view of a surgical splint 108. In thisexample, FIG. 20 shows the surgical splint 108 with the contours 350 ofthe patient's upper dentition 334. In this example, the surgical splintalso contains contours 350 on the opposing surface which correspond tothe contours of the patient's lower dentition 340. Surgical splintformation techniques are described in more detail in FIG. 1, withreference to 130 and 108. In some embodiments, each of the patient'steeth has a corresponding contour 350 in the splint 108. In oneembodiment, when the patient's teeth are placed in the splint, therelative positions of the upper 330 and lower 332 arch dentitionscorrect the diagnosed problem. In some embodiments, the splint 108contours 350 are of a depth that will hold the upper 330 and lower 332dentitions in the required relative positions but the splint 108 willalso be removable from both the physical model 128 and the patient P.

The various embodiments described above are provided by way ofillustration only and should not be construed to limit the claimsattached hereto. Those skilled in the art will readily recognize variousmodifications and changes that may be made without following the exampleembodiments and applications illustrated and described herein, andwithout departing from the true spirit and scope of the followingclaims.

What is claimed is:
 1. A method of fabricating surgical splints for usein a surgical procedure, the method comprising: obtaining athree-dimensional digital model of lower and upper arch dentitions of apatient having a dental condition; adjusting the relative position ofthe lower and upper arch dentitions with respect to each other in thethree-dimensional digital model using a computing device; adding atleast one relative positioning structure to the three-dimensionaldigital model using the computing device, wherein the relativepositioning structure includes separable first and second portions, thefirst portion connected to and extending from the upper arch dentitionand the second portion connected to and extending from the lower archdentition, wherein distal ends of the first and second portions havecomplementary mating features; generating a physical model of thepatient's corrected dentition from the three-dimensional digital model,the physical model including the at least one relative positioningstructure that connects the lower and upper arch dentitions of thephysical model at the adjusted relative position; and forming a surgicalsplint using the physical model.
 2. The method of claim 1, wherein thecomplementary mating features are male and female couplings.
 3. Themethod of claim 1, wherein adding the at least one relative positioningstructure comprises: prompting a user to identify a point on one of thedigital model of the lower and the upper arch dentitions; receiving aninput identifying a point; identifying a region surrounding the pointhaving a predetermined radius; generating a body of the relativepositioning structure extending from the region; and generating acoupling at an end of the body.
 4. The method of claim 3, wherein addingthe at least one relative positioning structure further comprises:identifying a second point corresponding to the identified point on anopposite one of the lower and upper arch dentitions; identifying asecond region surrounding the second point having the predeterminedradius; generating a second body of a second relative positioningstructure extending from the second region; and generating a coupling atan end of the second body, wherein the coupling at the end of the secondbody is complementary with the coupling at the end of the body to permitproper spacing and alignment of the lower and upper arch dentitions bymating the coupling with the second coupling.
 5. The method of claim 4,further comprising displaying the digital models of the upper and lowerarch dentitions including the relative positioning structure and thesecond relative positioning structure and prompting the user to confirmthat the relative positioning structure and the second relativepositioning structure are adequately spaced from teeth in the digitalmodels of the upper and lower arch dentitions.
 6. The method of claim 4,wherein when the relative positioning structure and the second relativepositioning structure are mated together, teeth of the lower and upperarch dentitions are spaced from each other by a distance appropriate fora thickness of the surgical splint.
 7. The method of claim 6, whereinforming the surgical splint comprises: inserting a pliable material intothe space between the lower and upper arch dentitions such that thepliable material includes an impression of at least some of the teeth ofthe lower and upper arch dentitions; and curing the pliable materialusing ultraviolet light to harden the material and reduce thepliability.
 8. The method of claim 1, generating a physical modelcomprises printing with a three-dimensional printer.
 9. The method ofclaim 1, wherein generating the physical model comprises milling thephysical model from one or more blocks of material.
 10. A method offabricating a splint, the method comprising: obtaining athree-dimensional digital model of lower and upper arch dentitions of apatient; adjusting the relative position of the lower and upper archdentitions with respect to each other in the three-dimensional digitalmodel using a computing device; adding at least one relative positioningstructure to the three-dimensional digital model using the computingdevice, wherein the relative positioning structure includes separablefirst and second portions, the first portion connected to and extendingfrom the upper arch dentition and the second portion connected to andextending from the lower arch dentition, wherein distal ends of thefirst and second portions have complementary mating features; generatinga physical model of the patient's corrected dentition from thethree-dimensional digital model, the physical model including the atleast one relative positioning structure that connects the lower andupper arch dentitions of the physical model at the adjusted relativeposition; and forming a splint using the physical model.
 11. The methodof claim 10, wherein the three-dimensional digital model of lower andupper arch dentitions of a patient has a natural alignment, and whereinthe splint is a non-surgical splint and is configured to provide atherapeutic effect by adjusting the alignment of the patient's upper andlower arch dentitions.
 12. A method of fabricating surgical splints foruse in a surgical procedure, the method comprising: obtaining athree-dimensional digital model of lower and upper arch dentitions of apatient having a dental condition; adjusting the relative position ofthe lower and upper arch dentitions with respect to each other in thethree-dimensional digital model using a computing device; adding atleast one relative positioning structure to the three-dimensionaldigital model using the computing device, wherein adding the at leastone relative positioning structure comprises: prompting a user toidentify a point on one of the digital model of the lower and the upperarch dentitions; receiving an input identifying a point; identifying aregion surrounding the point having a predetermined radius; generating abody of the relative positioning structure extending from the region;and generating a coupling at an end of the body; generating a physicalmodel of the patient's corrected dentition from the three-dimensionaldigital model, the physical model including the at least one relativepositioning structure that connects the lower and upper arch dentitionsof the physical model at the adjusted relative position; and forming asurgical splint using the physical model.
 13. The method of claim 12,wherein the complementary mating features are male and female couplings.14. The method of claim 12, wherein adding the at least one relativepositioning structure further comprises: identifying a second pointcorresponding to the identified point on an opposite one of the lowerand upper arch dentitions; identifying a second region surrounding thesecond point having the predetermined radius; generating a second bodyof a second relative positioning structure extending from the secondregion; and generating a coupling at an end of the second body, whereinthe coupling at the end of the second body is complementary with thecoupling at the end of the body to permit proper spacing and alignmentof the lower and upper arch dentitions by mating the coupling with thesecond coupling.
 15. The method of claim 14, further comprisingdisplaying the digital models of the upper and lower arch dentitionsincluding the relative positioning structure and the second relativepositioning structure and prompting the user to confirm that therelative positioning structure and the second relative positioningstructure are adequately spaced from teeth in the digital models of theupper and lower arch dentitions.
 16. The method of claim 14, whereinwhen the relative positioning structure and the second relativepositioning structure are mated together, teeth of the lower and upperarch dentitions are spaced from each other by a distance appropriate fora thickness of the surgical splint.
 17. The method of claim 16, whereinforming the surgical splint comprises: inserting a pliable material intothe space between the lower and upper arch dentitions such that thepliable material includes an impression of at least some of the teeth ofthe lower and upper arch dentitions; and curing the pliable materialusing ultraviolet light to harden the material and reduce thepliability.
 18. The method of claim 12, generating a physical modelcomprises printing with a three-dimensional printer.
 19. The method ofclaim 12, wherein generating the physical model comprises milling thephysical model from one or more blocks of material.
 20. A method offabricating a splint, the method comprising: obtaining athree-dimensional digital model of lower and upper arch dentitions of apatient; adjusting the relative position of the lower and upper archdentitions with respect to each other in the three-dimensional digitalmodel using a computing device; adding at least one relative positioningstructure to the three-dimensional digital model using the computingdevice, wherein adding the at least one relative positioning structurecomprises: prompting a user to identify a point on one of the digitalmodel of the lower and the upper arch dentitions; receiving an inputidentifying a point; identifying a region surrounding the point having apredetermined radius; generating a body of the relative positioningstructure extending from the region; and generating a coupling at an endof the body; generating a physical model of the patient's correcteddentition from the three-dimensional digital model, the physical modelincluding the at least one relative positioning structure that connectsthe lower and upper arch dentitions of the physical model at theadjusted relative position; and forming a splint using the physicalmodel.
 21. The method of claim 20, wherein the three-dimensional digitalmodel of lower and upper arch dentitions of a patient has a naturalalignment, and wherein the splint is a non-surgical splint and isconfigured to provide a therapeutic effect by adjusting the alignment ofthe patient's upper and lower arch dentitions.